Debt Payoff Calculator
Enter total debt, average annual interest rate, monthly payment you can make, minimum monthly payment required, additional monthly available, repayment strategy (avalanche highest-rate first or snowball smallest first), and any lump-sum you can throw at it now. See payoff months, payoff date, total interest, total paid, interest saved vs minimums, months saved, and whether minimum payment even covers interest. The math behind getting to zero.
Instant calculations · Editable fee assumptions · Export-ready results
Inputs
Values update results instantly. Adjust fee assumptions to match your seller dashboard.
Debt
Total balance owed
Average or highest rate for avalanche reference
Credit card minimum, typically 1-2% of balance
Strategy
Total you can pay toward debt each month
Extra beyond current payment
Avalanche: pay highest-rate first. Snowball: pay smallest balance first.
One-time extra payment
Results
Live estimates based on your inputs and editable fee assumptions.
Current debt
$35,000.00
Starting balance.
Effective monthly payment
$800.00
Monthly + additional + amortized lump.
Payoff months
74
Months to zero at your payment.
Payoff months from now (approx)
74
Same number, for display as months.
Total interest paid
$23,688.96
Interest over life.
Total paid (principal + interest)
$58,688.96
All payments sum.
Interest saved vs minimum payment
$0.00
Compared to paying only minimum.
Months saved vs minimum
0
Time saved vs minimum.
Payoff months at minimum only
9,999
If you paid minimums.
Minimum payment covers interest?
Warning: minimum payment does not cover monthly interest — balance will never decrease paying only minimum.
If minimum < monthly interest, never pays off.
What this means
Debt $35000 minus $0 lump = $35000 to amortize at $800/mo (avalanche). Payoff 74 months. Interest $23689 total paid $58689. vs minimum never saves $0 and 0 months. Warning: minimum payment does not cover monthly interest — balance will never decrease paying only minimum.
Debt balance decline over time
Interactive breakdown of fees, costs, and remaining profit.
Distribution
- Principal$35,000.0059.6%
- Interest paid$23,688.9640.4%
Total $58,688.96 · 2 segments · interactive
Line-item breakdown
Dollar amounts, share of revenue, and visual proportion.
- Total debt
- $35,000.00
- Lump sum reducing debt
- $0.00
- Principal to amortize
- $35,000.00
- Monthly payment input
- $800.00
- Additional monthly
- $0.00
- Effective monthly
- $800.00
- Annual rate
- 18.5%
- Monthly rate
- 1.5%
- Payoff months
- 74
- Total interest paid
- $23,688.96
- Total paid
- $58,688.96
- Minimum payment
- $350.00
- Minimum payoff months
- 9,999
- Interest saved vs minimum
- $0.00
- Months saved vs minimum
- 0
Assumptions used
- • Start $35000.00 = $35000.00−$0.00 lump
- • Effective $800.00 = $800.00+$0.00
- • Monthly rate 1.5417% = 18.50%/12
- • Payoff checks if payment $800.00 <= interest $539.58 → never
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Debt Payoff Calculator
Generated 8/4/2026, 2:49:41 PM · Currency USD
Inputs
- Total debt balance: 35000
- Annual interest rate %: 18.5
- Monthly payment you will make: 800
- Minimum monthly payment required: 350
- Additional monthly available: 0
- Payoff strategy: avalanche
- One-time lump sum payment: 0
Results
- Total debt: $35,000.00
- Lump sum reducing debt: $0.00
- Principal to amortize: $35,000.00
- Monthly payment input: $800.00
- Additional monthly: $0.00
- Effective monthly: $800.00
- Annual rate: 18.5%
- Monthly rate: 1.5%
- Payoff months: 74
- Total interest paid: $23,688.96
- Total paid: $58,688.96
- Minimum payment: $350.00
- Minimum payoff months: 9,999
- Interest saved vs minimum: $0.00
- Months saved vs minimum: 0
Interpretation
Debt $35000 minus $0 lump = $35000 to amortize at $800/mo (avalanche). Payoff 74 months. Interest $23689 total paid $58689. vs minimum never saves $0 and 0 months. Warning: minimum payment does not cover monthly interest — balance will never decrease paying only minimum.
How it works
Methodology & formulas
This calculator is transparent by design. Review the steps and formulas so you can trust the estimate and adjust assumptions when your dashboard differs.
Calculation steps
- 1Reduce balance by lump sum immediately.
- 2Combine monthly and additional for effective payment.
- 3If effective <= balance×monthlyRate, flag as never pays off.
- 4Simulate month-by-month: interest=balance×rate, principal=payment−interest, balance−=principal.
- 5Same simulation for minimum payment path for comparison.
- 6Calculate interest saved and months saved differences.
- 7Explain snowball vs avalanche tradeoffs in FAQs.
Formulas
- r = annual%/100 /12
- principalStart = totalDebt − lumpSum
- effective = monthlyPayment + additional
- if effective <= principal×r → never pays off
- months = -ln(1 − principal×r / effective)/ln(1+r)
- totalPaid = months×effective + lump
- totalInterest = totalPaid − totalDebt
- monthsMinimum = -ln(1 − principal×r / minimum)/ln(1+r)
- interestSaved = minimumInterest − yourInterest
Important assumptions
- Effective payment = monthlyPayment + additionalMonthlyAvailable.
- Lump sum reduces principal immediately before amortization starts.
- Monthly rate = annual%/100 /12.
- Payoff months solves via logarithmic formula if payment > interest: n = -ln(1 - P×r / payment) / ln(1+r). Simulation used for accuracy with checks.
- Total paid = payoffMonths × effectivePayment (plus lump).
- Total interest = totalPaid − (debt − lump).
- Minimum payoff months calculated same with minimum payment.
- Interest saved vs minimum = minimumTotalInterest − yourTotalInterest.
- If payment <= interest, loan never pays off — infinite months.
- Strategy field stored for display; single-debt math same for both, but explanation distinguishes avalanche (save interest) vs snowball (psychological wins).
Worked example
$35K debt at 18.5%, $800/mo payment
$35K balance 18.5% annual, $800 monthly, minimum $350, $0 extra, avalanche, $0 lump. Effective $800. Payoff ~62 months (5.2 years). Total interest $14,600 total paid $49,600. Minimum $350 takes ~183 months 15+ years and $29K extra cost. Saves $14K+ interest and 121 months.
FAQ
Common questions
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